Sewing machine



July 21, 1936. F, CEDERQUIST 2,048,427

' SEWING MACHINE Filed Oct. 22, 1954 Ira/amid) feed dog.

the Operating link broken away. J i

r f Figure 5 is a detail view the feed dog member.

Patented July 21, 1936 I UNITED STATES PATENT OFFICE SEWING MACHINE Alf F. Cederquist, St. Louis, Mo.

I Application October 22, 1934, Serial No. 749,355

5 Claims. (01. 112-215) This invention relatesto sewing machines and more particularly to feed dogs for post sewing machines. Heretofore this type of sewing machine employed a feed dog comprising an elongated member having. its lower end fixed to a link pivotally andslidably mounted on thepost andhaving the face of its upper end serrated and adapted to engage and advance the work pressed thereagainst by the presser wheel. As this serrated face wore out quickly, it was'necessary at frequent intervals to detachsaid feed dog and resharpen the teeth or serrations- Thus new adjustment of the feed dog was necessaryateach sharpening operation andthe entire member had to be discarded in a very short time due to these numerous sharpenings.

One of the objects of the present invention is to provide a'two-part feed dog, namely, a member fixed to the operating link and a member having a serrated face and detachably mounted on the first member, saidserrated face member, being disk-shaped or polygonal shape and being axially "mounted on said support member and adjustable to present anyone of the peripheral serrated portions in working position.

' Another object of the invention is to provide a "feed dog assembly having a detachable serrated face member which can be detached and replaced with a new one without disturbing the connection between the support member and the actuating link.

An additional object of the invention is to provide a feed dog construction of the character described which is eflicient in operation, has a long periodof usefulnessand reduces the cost of maintenance of the sewing machine,

With these and other objects in view, my invention consists of certain novel features of construction and arrangement of parts, hereinafter .more fully described and claimed, and illustrated in the accompanying drawing, in which Figure 1 is a fragmental side elevational view of a post sewing machine showing part of the head and some of the mechanism- -for actuating the Figure2 is an enlarged top planview of the l feed dog assembly.

Figure 3 is a front elevational view of same with Figure 4 is a vertical cross section taken through the feed dog assembly l v l of a modified form of ur 6 h iz n alkcr s c i n taken on line 65 of Figure 3.

"by arrows in Figure 1.

Referring by numerals to the accompanying drawing, I represents a head of a post sewing machine and II the post on which the feed dog mounted on said pin and occupying said slot 20.

The width of the block is substantially the same as that of the slot but the length of the latter is greater so that said link I9 is free to move longitudinally a suitable distance.

' Thelow'er end of the link [9 is connected to suitable operating mechanism which imparts t0 the upper end of said link movement indicated This mechanism includes a pair of rock shafts 24 and 25 arranged below and in spaced-apart relation with each other and 'the lower end of said link. Fixed to shaft 25 is a vertically projecting rock arm 26 to the upper end of which is pivotally connected the outer end of a horizontally disposed arm 21. This arm extends toward shaft 24 past the lower end of said. link [9 and is pivotally connected to said end, as indicated at 2B. Thus the actuation of said rock shaft 25 imparts rocking or pivotal movement to said link, with the pin 2| as the axis.

The shaft 24 has fixed thereon one end of a rock arm 29 which extends horizontally toward the outer end of arm 21 and carries a pin or screw 30 on which is pivotally mounted a block 3|. The

outer end of arm 21 is bifurcated to form a horizontally disposed slot 32 and the block 3| has a sliding bearing therein. Thus the actuation of rock shaft 24 rocks arm 29 and through the connection thereof with arm 21 imparts to said link l9 longitudinal movement.

This longitudinal movement is in time relation with the oscillating or rocking movement so that the cycle of movement of the upper end of said link is to the right (restoring movement), then upwardly, then to the left (work advancing movement); and then downwardly to repeat the cycle of operation, as indicated in dotted lines an arrows in Figure 1.

A needle plate 33 is fixed to the upper end of post ll and is: provided with aslot 33a. The

construction hereinbefore described is one commonly used in post sewing machines.

only the upper portion of member 34 and the member 44 is of octagonal shape, thereby My invention relates to the feed dog assembly. Whereas, heretofore the feed dog or serrated face was formed on the upper end of the member fixed to link I9, I provide a feed dog member 34 which is detachable from the support member 35, which latter is fixed to the upper end of link [9.

This support member 35 has a shank portion or lower end 35a which is reduced in width and is provided with a longitudinally disposed slot 36 through which extends a screw 31. This screw is screw-seated in the upper end of link is and serves to'hold said member 35 in fixed position on said link, while slot 36 permits longitudinal adjustment of said member 35. In order to hold key l9a. The upper end of member 35-isformed" .onone side with ;a circular recess 38 which is of sufficient diameter to cut away the central portion ,ofth'e upper end of said member, as indicated at 38a. Fixed in said recess by a set screw thefeed dog member 34 which, in the instant case is disk-shaped and has its peripheral surface serrated, as indicated at 4B. The diameteroi this feed dog 34 is such that the upper portion thereof projects outwardly through the opening 339, thereby disposing the serrated face of saidupper portion above the upper end of niember 3 in working-engaging and advancing position. member 35 is thicker than the thickness of disk 34, the upper end of said member 35'is out away as-indicated at 4|, so that upper ends of the reducedside portions of member 35 extend upwardly through the slot 33a in needle plate 33. The inner side of the upper end pf member 3 5 is formed concave, as indicated at 42, to conform to the chamber injpost H, which chamber is round in cross section and contains the loop forming mechanism (not shown).. The centralportion of the shoulder 4| is rounded or tapered downwardlyas' indicated at Ma, in order to eliminate a fiat horizontal surface in the path pf the, needle and prevent breakage of the latter incase theppoint of thejneedle is bent. or forced thereagainst, Byrounding this portion the point of the needle is deflected or guided downwardly against the concave face 42 without causing breakage of the needle. 7 V

The roller presser is disposed above the feed dog member 34 and the work is clamped therebetween and is advanced by the actuation of said feed dog through the oscillating and longitudinal movement of link Hi.

When the exposed portion of the feed dog 34 is worn out, set screw 39 isloosened to permit partial rotation of said member 34 so as to permit a new serrated surface to be placed in operating position. 'When the entire serrated peripheral surface of the feed dog has been worn out, the disk 34 can be removed and replaced by. a new one or the old one can be resharpened. .j In, the form shown in Figure 5, the feed dog providing-eightserrated faces 45 for use.

, The work engaging member being formed separate from the supporting member, it :can be replaced with a new one without removing or replacing the support member. Furthermore, the work engaging member can be case-hardened and when worn out'the temper can be drawn out and the serrated face thereof sharpened and then again case-hardened without requiring said support member to be subjected to these operations.

By forming the work engaging member of a circular shape or a polygonal shape, a large serrated surface is provided so that said member can be adjusted to present a new peripheral portion into work-engaging position as the old one is worn out.

The opening in the needle plate is wide enough to allow the upper portion of the work engaging member and of the upper ends of the reduced side portions of the support member to project "upwardly therethrough. The needle in moving into the upper end of post II to cooperate with the loop forming mechanism operates through a needle opening in said needle plate. When the point of the needle is bent accidentally the corresponding side of the work engaging member and of the support engage the deflected point and guide it, and by virtueof the tapered or rounded portion on said support the needle is forced back to its normal position, thereby preventing breakage thereof.

' Thus it will be seen that my invention not only increases the life and usefulness of the workengaging'memb'er but also effects a great saving by reducingbreakage of needles.

I claim:

1. in a sewing machine of the character described, the combination with a post and a vertically disposed link pivotally and slidably mounted there'om'of a feed dog device comprising a vertically disposed support member fixed to the upper end of said link,'and a feed dog member detachably secured to said support member, a serrated perimeter on said feed dog member, said feed dog member being positionable on said support member to present any portion of its serrated perimeter in work engaging and advancing p0- sition.

2. In .a sewing machine of the character described, the combination with a post and a vertically disposed link pivotally and slidably mounted thereon, of a feed dog construction comprising a vertically disposed support member detachably feed dog member axially on said support member whereby said feed dog member can be turned on-- its axis to present any portion of its serrated surface in work engaging and advancing position.

3. ma sewing machine of the character described, the combination of a post, a vertically disposed link pivotally and slidably mounted-.60

thereon, a vertically disposed support carried by the upper end of said link, a feed dog fixed to the upper end of saidsuppflrt with a portion disposed above the upper end of said support in work enhaving its perimeter formed with a serrated face,

and means for holding said feed dog in fixed relagaging and advancing position, said feed dog bring any portion'ofthe serrated perimeter there- 7 of in work engaging position.

to the upper endof said link, a feed dog fixed to said support and having a portion projecting above the upper end of said support for engaging and advancing the work, said feed dog being disk-shaped and having its periphery provided with a serrated surface, and means for securing said feed dog axially to said support whereby said feed dog can be adjusted to move a fresh portion of its peripheral serrated face into work engaging position.

5. In a post sewing machine, a feed dog device comprising a vertically disposed link mounted for oscillating and reciprocating movement, a support fixed to the upper end of said link, a disk having its periphery provided with a serrated surface, and a set screw for securing said disk in a fixed position on said support with the upper portion of said disk disposed above the upper end of said support in a work engaging and advancing position, said set screw being releasable to permit adjustment of said disk to bring a fresh portion of the peripheral serrated surface thereof into Work engaging position.

ALF F. CEDERQUIST. 

